Characteristics and community diversity of a wheat straw-colonizing microbial community

A microbial community named WSD-5 was successfully selected from plant litter and soil after longterm directed acclimation at normal temperature. After 15 days of cultivation at 30°C, the degradation rate of wheat straw by WSD-5 was 75.6%. For cellulose, hemicellulose and lignin, the degradation rates were 94.2, 81.9 and 21.3%, respectively. The optimal pH for filter paper, CMCase, avicelase, β- glucosidase and xylanse activities was 6.24, 6.24, 5.91, 5.91 and 6.24, respectively. The optimal reaction temperature for all enzyme activity was 55°C. Filter paper enzyme, cellulase and xylanase were secreted from the degradation of wheat straw by WSD-5. The highest filter paper, cellulose endonuclease (CMCase), cellulose exonuclease (avicelase), β-glucosidase and xylanase activities were 1.30, 4.35, 0.60, 0.43 and 15.16 U/ml, respectively. A library of bacterial and fungal ribosomal gene sequences obtained from the community showed the presence of Ochrobactrum sp, Coprinus cinereus and Pseudallescheria boydii . To our knowledge, this was the first report of a microbial community which consisted of bacteria and fungi and was selected in the presence of wheat straw to produce extracellular filter paper enzyme, cellulase and xylanase. Key words: Microbial community, lignocellulose degradation, filter paper activity, CMCase, avicelase, β- glucosidase, xylanase.